Presentation on theme: "Collapsing Trachea Mark Bohling, DVM Diplomate, American College of Veterinary Surgeons Assistant Professor of Surgery University of Tennessee College."— Presentation transcript:
Collapsing Trachea Mark Bohling, DVM Diplomate, American College of Veterinary Surgeons Assistant Professor of Surgery University of Tennessee College of Veterinary Medicine
What is Tracheal Collapse? Normal airflow dynamics in respiration Inspiration Expansion of chest by muscles of respiration Pressure gradient - chest negative Effect on the air conduit: Thorax - expansion Neck - compression Expiration Reverse effects
History of Collapsing Trachea in Veterinary Medicine Described as early as 1960 Review of early treatments Single plastic tube Ventral chondrotomy Modified ventral chondrotomy Dorsal membrane plication
Tracheal Collapse in Other Species Tracheal collapse in human beings History Dates to 1930’s Similarities Softening of tracheal cartilage Lateral collapse (same as dorsoventral in dogs) Differences Classification Primary vs secondary collapse Pediatric vs adult collapse
Tracheal Collapse in Other Species Tracheal collapse in large animals Horses Congenital Secondary to laryngeal paralysis Cattle Acquired neonatal Tracheal collapse in birds Bordetella avium in turkeys
Tracheal Collapse in the Dog Miniature breeds Middle aged to older Other risk factors More pronounced in obese individuals
Internal Stenting What is a stent? History of stenting History of tracheal stenting Modern stents and stent materials Stents in veterinary medicine
Ultraflex ® Stent Radiopaque, self-deployed 4 - 8 cm length, 10 - 20mm diameter Made of nitinol (nickel-titanium alloy) Proximal or distal deployment Single strand, open loop knitted design (flexible, contourable) Boston Scientific/ Microvasive.
Stent Fracture Originally thought to be due to bending stresses All brands/types of nitinol stents can fracture - there is NO unbreakable stent At this time, removal is best option - BUT - not for the fainthearted!
Rings vs. Stents Cost to client (stent more expensive) Stents are easier and quicker Complication rate similar Neither cure, only control symptoms Stent placement requires expensive equipment Rings require surgical expertise Lack of proper size stent
A “typical” case with tracheal rings Day 1: Preop workup (bloodwork, radiographs, tracheoscopy) Day 2: Surgery Postop recovery in ICU Day 3: Still in ICU Day 4: Discharged from hospital Home monitoring – continue medical therapy 2 – 4 weeks Recheck time variable, depends on outcome Long term outcome usually good, but…
A “typical” case with tracheal stent Day 1: Workup as for rings. Order stent from supplier Day 2: Stent arrives (usually). Stent is placed in a 30 minute procedure and patient recovers in ICU Day 3-4: Recovery in ICU Day 5: Discharge from hospital Home care for 2-4 weeks Re-check tracheoscopy at one month to check if stent is embedded
Miss Piggy - Stent disaster case #1 Signalment: Miss Piggy 6 year old spayed female Yorkie Body weight 13 lbs (BCS 8/9!!) Grade III/VI heart murmur History: Coughing for past 2 years, getting worse past yr Presented to emergency clinic Saturday night Unable to breathe, cyanotic Oxygen dependent
Miss Piggy Presentation at UT Still oxygen dependent Tracheoscopy findings: Cervical - Grade 3 entire length Thoracic - Grade 3-4 entire length Left main bronchus Grade 2-3 Plan: stent entire trachea Poor anesthetic risk Guarded prognosis given
Miss Piggy Stent placement Thoracic stent 1 cm cranial to carina 5mm overlap at thoracic inlet Cervical stent 1 cm caudal to cricoid
Miss Piggy Postop first 24 hours Doing well in oxygen Next day… Trial period out of oxygen - - cough and cyanosis Back to oxygen and medical mgmt Antitussives Bronchodilators
Miss Piggy 3rd postop day Brief trial out of oxygen - - same result Still looks good in oxygen 4th postop day 4am “can’t get comfortable” 7am - 7pm: awake all day 9pm: lung sounds getting “harsh” 11pm: crackles ausculted
Miss Piggy 5th day…. Early am hours - No response to bronchodilators or diuretics Patient very tired, has not slept in 24 hours 9am - respiratory failure
Stent disaster #2 - Tuffy Signalment: 4 year old male castrated Yorkie BW 8 lbs, BCS 6/9 History: Started at 2 years old Now coughs at slightest exertion Cyanotic with mild exercise
Tuffy Tracheoscopy: Cervical collapse - grade 3 Thoracic collapse - also grade 3 Bronchi both open Plan: Stent entire trachea
Tuffy Immediate postop Doing well! 3 weeks later… “gagging” noticed Recheck at UT BOTH stents fractured Tracheal lumen open but small Lots of exudate
What next? Immediate plan Stabilize his condition Antibiotics Some antitussives Definitive plan Stent removal Re-stent over the broken ones
Tuffy – the outcome Survived the procedure! Immediate improvement in breathing Went home doing well, but some cough Continued to improve Still coughs some Overall quality of life – better than before Cost to owner: $5K+ total, lots of gray hair!
Future Needs Immediate needs: Improved surgical treatment options Less breakable stents Improved rings - can we go intrathoracic? Improved medical management options Cough suppression with less sedation Tracheal cartilage - can malacia be arrested?
Future Needs Long-term needs Greater understanding of the etiology of this process What is happening at the cellular and molecular level? Identification of molecular/genetic marker(s) Creation of a breed registry for this disease Apparent genetic cause Can we “breed it out”?
Special thanks to: Dr DJ Krahwinkel Sue Schwarten Danielle Browning UT photo and media services Linda Hicks and Mr T